(原文件名:晶振实际为24M，J3接315M接收模块.JPG)
代码如下：
#include<AT89X52.h>

sbit PIN=P3^3;

sbit LockLED1=P0^0;
sbit LockLED2=P0^1;
sbit PortLED1=P0^2;
sbit PortLED2=P0^3;
#define SPort P2

const RMax=3000;   

idata unsigned int RData[48];
unsigned char DP=0;
unsigned int T0Value=0;
const unsigned char CAdr[8]="F0FF0100";
bit PortLockBit;

void LockPort(void){
  PortLockBit=1;
  LockLED1=0;
  LockLED2=0;
}
void UnlockPort(void){
  PortLockBit=0;
  LockLED1=1;
  LockLED2=1;
}
void OpenPort(void){
  if(PortLockBit==0){
    PortLED1=0;
    PortLED1=0;
        SPort=0x00;
  }
}
void ClosePort(void){
  if(PortLockBit==0){
    PortLED1=1;
    PortLED1=1;
        SPort=0xFF;
  }
}
bit CheckAdr(void){
  unsigned char i;
  bit j=1;
  for(i=0;i<8;i++){if(CAdr!=RData)j=0;}
  return j;
}

int MaxValue(void){
  unsigned char i;
  unsigned int a=0x0000;
  for(i=0;i<48;i++){if(RData>a)a=RData;}
  return a;
}
int MinValue(void){
  unsigned char i;
  unsigned int a=0xFFFF;
  for(i=0;i<48;i++){if(RData<a)a=RData;}
  return a;
}
void Decode(void){
  unsigned int MaxVal,MinVal,AverAge;
  unsigned char i;
  bit IsVaild=1;
  MaxVal=MaxValue();MinVal=MinValue();
  if((MaxVal-MinVal)>=40){
    AverAge=(MaxVal+MinVal)/2;
        for(i=0;i<24;i++){if((RData>AverAge)!=(RData[i+24]>AverAge))IsVaild=0;}
        if(IsVaild){
          for(i=0;i<12;i++){
            if(RData[i*2]>AverAge&&RData[i*2+1]>AverAge){RData='0';}
            else if(RData[i*2]>AverAge&&RData[i*2+1]<AverAge){RData='F';}
            else if(RData[i*2]<AverAge&&RData[i*2+1]>AverAge){RData='E';}//ERROR
            else if(RData[i*2]<AverAge&&RData[i*2+1]<AverAge){RData='1';}
            }
          if(CheckAdr()){
                if(RData[8]=='1')LockPort();
                if(RData[9]=='1')ClosePort();
                if(RData[10]=='1')OpenPort();
                if(RData[11]=='1')UnlockPort();
          }
        }
  }
}
//---------
void InitINT1(void){
  EA=1;
  EX1=1;
  IT1=1;
}

void INT1Interrupt(void) interrupt 2{
  T0Value=0;
  TH0=0;TL0=0;
  while(PIN==0);
  if(T0Value==0){T0Value=TH0*0x100+TL0;}
  EA=0;
  if(T0Value>RMax&&DP!=24){DP=0;}
  else if(T0Value<=RMax)RData[DP++]=T0Value;
  if(DP==48){
    Decode();
        DP=0;
  }
  EA=1;
}

void InitTimer0(void)
{
    TMOD |= 0x01;
    TH0 = 0x00;
    TL0 = 0x00;
    EA = 1;
    ET0 = 1;
    TR0 = 1;
}

void Timer0Interrupt(void) interrupt 1
{
    T0Value=0xFFFF;
}

void main(){
  UnlockPort();
  ClosePort();
  LockPort();
  InitTimer0();
  InitINT1();
  while(1);
}